In various communication and computer systems, serial communications are used to transmit data over a communications bus. In a serial communication system, data is transmitted one bit at a time in sequence onto the communications bus, and the transmitted data is then received in the same sequence by one or more devices coupled to the communications bus. There are many different standards and protocols available for use in serial communications systems.
As an example of a serial bus communication protocol, “Controlled Area Network” (abbreviated “CAN”) is a standard directed to a serial bus system that can be used to connect microcontrollers, sensors, and actuators in real-time control applications. A version of a CAN protocol is High Speed CAN (abbreviated “HS-CAN”), and is directed to a communication system based on two-conductor differential network. In various examples, the two-conductor differential network includes a twisted-pair cable as the bus.
Devices coupled to the two-conductor CAN network or the HS-CAN network are referred to as CAN nodes. A CAN system requires at least two CAN nodes to be coupled to the CAN network. Data is communicated on the CAN or HS-CAN bus by providing two different levels of a voltage differential between the two conductors of the CAN bus, the two conductors referred to as the CAN High line and the CAN Low line. In various examples, CAN bus and HS-CAN bus are considered to be a non-return-to-zero (NRZ) bus system. A first differential voltage level provided between the CAN High line and the CAN Low line represents a first data state or data bit, referred to as the “RECESSIVE” state, and is representative of a logic “1,” and a second differential voltage level, different from the first differential voltage level and referred to as the “DOMINANT” state, is representative of a logic “0”. In various examples, communication protocols used in CAN bus communications, referred to as “CAN-FD” allow for data transmission rates up to 5 Mbits/second.